Biomedical subjects

C C Lin

Publications and source records attributed to C C Lin.

At least 163 records · Page 9Linked to original sources

PubMed1999

Inhibition of bradykinin-induced phosphoinositide hydrolysis and Ca2+ mobilisation by phorbol ester in rat cultured vascular smooth muscle cells.

Regulation of the increase in inositol phosphate (IP) production and intracellular Ca2+ concentration ([Ca2+]i by protein kinase C (PKC) was investigated in cultured rat vascular smooth muscle cells (VSMCs). Pretreatment of VSMCs with phorbol 12-myristate 14-acetate (PMA, 1 microM) for 30 min almost abolished the BK-induced IP formation and Ca2+ mobilisation. This inhibition was reduced after incubating the cells with PMA for 4 h, and within 24 h the BK-induced responses were greater than those of control cells. The concentrations of PMA giving a half-maximal (pEC50) and maximal inhibition of BK induced an increase in [Ca2+]i, were 7.8 +/- 0.3 M and 1 microM, n = 8, respectively. Prior treatment of VSMCs with staurosporine (1 microM), a PKC inhibitor, inhibited the ability of PMA to attenuate BK-induced responses, suggesting that the inhibitory effect of PMA is mediated through the activation of PKC. Paralleling the effect of PMA on the BK-induced IP formation and Ca2+ mobilisation, the translocation and downregulation of PKC isozymes were determined by Western blotting with antibodies against different PKC isozymes. The results revealed that treatment of the cells with PMA for various times, translocation of PKC-alpha, betaI, betaII, delta, epsilon, and zeta isozymes from the cytosol to the membrane were seen after 5 min, 30 min, 2 h, and 4 h of treatment. However, 24-h treatment caused a partial downregulation of these PKC isozymes in both fractions. Treatment of VSMCs with 1 microM PMA for either 1 or 24 h did not significantly change the K(D) and Bmax of the BK receptor for binding (control: K(D) = 1.7 +/- 0.2 nM; Bmax = 47.3 +/- 4.4 fmol/mg protein), indicating that BK receptors are not a site for the inhibitory effect of PMA on BK-induced responses. In conclusion, these results demonstrate that translocation of PKC-alpha, betaI, betaII, delta, epsilon, and zeta induced by PMA caused an attenuation of BK-induced IPs accumulation and Ca2+ mobilisation in VSMCs.

Animals↗

PubMed1999

Synthesis of sialyl Lewis x mimetics as selectin inhibitors by enzymatic aldol condensation reactions.

Several D-mannosyl phosphate/phosphonate derivatives have been enzymatically prepared as sialyl Lewis x tetrasaccharide mimics, which showed strong-to-moderate inhibition against E-, P-, and L-selectins. The synthesis of these mimics is very straightforward; mannosyl aldehyde derivatives are condensed with dihydroxyacetone phosphate (DHAP) in the presence of a DHAP-dependent aldolase to provide mannosyl phosphates.

Carbohydrate Conformation↗

PubMed1999

Primary oral squamous cell carcinoma: an analysis of 703 cases in southern Taiwan.

We retrospectively analyzed the records of 703 cases of oral squamous cell carcinoma (SCC) collected from 1 January 1985 to 31 December 1996 at a teaching hospital in southern Taiwan, to identify the characteristics of patients and factors associated with survival. There was an overwhelming male predominance (male:female = 15:1). The mean age of the patients was 52. The peak age of oral SCC patients declined from 50 to 59 years in the first six years (1985-1990) and 40-49 years in the last six years (1991-1996). The most common site of oral SCC was the buccal mucosa with 263 patients (37.4%). Most patients (346/703 patients; 49.2%) had stage III cancer. The most common site of occurrence of SCC was the buccal mucosa (263/703 patients; 37.4%), both overall and in patients who chewed betel quid alone or in combination with cigarette smoking and/or alcohol consumption; the tongue was the most common site among patients without any oral habits (18/48 patients; 37.5%). Furthermore, the age of occurrence was on average 6-12 years younger among patients who chewed betel quid than in those who did not. Of the 703 patients, 496 received treatment with surgery, chemotherapy, and/or radiation therapy. Of these, 209 (42.1%) died. The cancer stage significantly influenced mortality: the 5-year survival rate in patients treated from 1985 to 1991 was 72% in those with stage I, 38.9% in those with stage II, 26.7% in those with stage III, and 11.8% in those with stage IV cancer. Six variables were found to significantly affect survival: tumor size, lymph node involvement, surgery, betel quid chewing, staging, and histological differentiation (all p < 0.05, Kaplan-Meier analysis with log rank test). Of these, surgery and cancer stage independently affected survival in a proportional hazards model (both p < 0.0001). Therefore, the early surgical intervention, and the withdrawal from oral habits, especially betel quid chewing, will be advantageous to patients' survival.

Adolescent↗

PubMed1999

Acetophenone glycosides from thyme (Thymus vulgaris L.).

Four acetophenone glycosides were isolated from the butanol-soluble fraction of thyme extracts. Their structures were determined by spectral methods (MS, NMR, and 2D-NMR). Among them, two new compounds, 4-hydroxyacetophenone 4-O-[5-O-(3, 5-dimethoxy-4-hydroxybenzoyl)-beta-D-apiofuranosyl]-(1-->2)-beta-D -gl ucopyranoside (1) and 4-hydroxyacetophenone 4-O-[5-O-(4-hydroxybenzoyl)-beta-D-apiofuranosyl]-(1-->2)-beta-D-+ ++gluc opyranoside (2), were determined. Compound 1 showed weak cytotoxicity, inhibiting DNA synthesis of human leukemia cells.

Acetophenones↗

PubMed1999

Conservation of human gamma-X centromeric satellite DNA among primates with an autosomal localization in certain Old World monkeys.

Gamma-X satellite DNA is a 220-bp tandemly arranged repetitive DNA with specificity for the centromeric region of the human X chromosome. The conservation of this human X centromeric satellite DNA sequence in primate species was evaluated by comparative fluorescence in-situ hybridization to metaphase chromosome preparations of the great apes and three Old World monkeys. Homologous gamma-X DNA were detected at centromeric locations in all six primate species. For the great apes, gamma-X was exclusively localized to the centromeric regions of the X chromosomes. Among the Old World monkeys studied, only the golden monkey exhibited localization to the X chromosome. In the black-and-white colobus and the pig-tailed macaque, human gamma-X sequences were localized to the pericentromeric regions of autosomes 1 and 4, respectively.

Animals↗

PubMed1999

Diagnosis of zygosity by questionnaire and polymarker polymerase chain reaction in young twins.

We developed a zygosity questionnaire for use in young twins and assessed its validity using the results of DNA diagnosis. The participants were divided into two groups: 105 pairs of adolescent twins (12-16 years old), 47 pairs of child twins (2-12 years old), and their respective parents. The DNA diagnosis of zygosity was made with polymarker polymerase chain reaction (PCR) amplification of five loci, using the AmpliType PM PCR Amplification and Typing Kit; this method has an accuracy rate of 99.0%. A parsimonious model for each sample was established using stepwise logistic regression analysis of the 20 items of the questionnaire. The total accuracy rate of the model was satisfactory for both parental reports (three items) and self-reports (three items) of adolescent twins (97.4 and 95.6%, respectively), while that for parental reports on child twins (two items) was less satisfactory (92.5%). For adolescent twins, if DNA diagnostic workups were limited to those with discordant reports either from themselves or from their parents, the accuracy rate increased to 100% for parental reports and 98% for self-reports.

Adolescent↗

PubMed1999

Development of sustained attention assessed using the continuous performance test among children 6-15 years of age.

The Continuous Performance Test (CPT) is a widely used measure of sustained attention, which may rely on the efficiency of cognitive inhibition. We examined the relationships of age and sex with CPT performance among 341 randomly selected school children 6-15 years of age. Multiple regression analyses revealed that the hit rate, false alarm rate, and sensitivity of both the undegraded and the degraded CPT were associated with age by a quadratic relationship. The age-development curves for the hit rate and sensitivity were convex, whereas that for the false alarm rate was concave. Sex was associated with the hit rate and sensitivity on the degraded CPT only. Our findings are consistent with the hypothesis that sustained attention develops during the primary school ages. The data reported are essential for identifying children with conditions associated with sustained attention deficit, such as attention-deficit hyperactivity disorder, as well as those at an increased risk for developing schizophrenia.

Adolescent↗

PubMed1999

The antiplatelet activity of PMC, a potent alpha-tocopherol analogue, is mediated through inhibition of cyclo-oxygenase.

PMC, a potent alpha-tocopherol derivative, dose-dependently (5-25 microM) inhibited the ATP-release reaction and platelet aggregation in washed human platelets stimulated by agonists (collagen and ADP). PMC also dose-dependently inhibited the intracellular Ca2+ mobilization, whereas it did not inhibit phosphoinositide breakdown in human platelets stimulated by collagen. PMC (10 and 25 microM) significantly inhibited collagen-stimulated thromboxane A2 (TxA2) formation in human platelets. On the other hand, PMC (25 and 100 microM) did not increase the formation of cyclic AMP or cyclic GMP in platelets. Moreover, PMC (25, 100, and 200 microM) did not affect the thromboxane synthetase activity of aspirin-treated platelet microsomes. PMC (10 and 25 microM) markedly inhibited the exogenous arachidonic acid (100 microM)-induced prostaglandin E2 (PGE2) formation in the presence of imidazole (600 microM) in washed human platelets, indicating that PMC inhibits cyclo-oxygenase activity. We conclude that PMC may exert its anti-platelet aggregation activity by inhibiting cyclooxygenase activity, which leads to reduced prostaglandin formation; this, in turn, is followed by a reduction of TxA2 formation, and finally inhibition of [Ca2+]i mobilization and ATP-release.

Antioxidants↗

PubMed1999

The advisability of implementing cholesterol screening in school-age children and adolescents with a family history of cardiovascular disease and hyperlipidaemia.

BACKGROUND: The family basis of coronary heart disease is well recognized and it is important for family physicians to assess whether children have elevated cholesterol levels. OBJECTIVES: We aimed to evaluate the advisability of implementing cholesterol screening in children with a family history of cardiovascular disease and hyperlipidaemia. METHODS: We conducted a cross-sectional study in Taiwan from February to June 1996. There were 47,800 students in the population. A total of 4520 students were recruited by two-stage sampling. All the participants were required to fill out a structured questionnaire. RESULTS: The response rate was 92.5%. Our results show that 16-18% of the children had a positive family history of cardiovascular disease or hyperlipidaemia. Children with a family history of hyperlipidaemia were significantly more likely to have elevated total cholesterol and low-density lipoprotein cholesterol than those without such a history (both odds ratios: 1.4, P < 0.05). Positive predictive values of hyperlipidaemia were less than 13% based on family history. More than 75% of children with abnormal lipid levels would be missed. CONCLUSIONS: The data suggest that parents' self-reported family history is an ineffective means of identifying children with elevated serum lipid levels in Taiwan. Further research and modification of current National Cholesterol Education Program Panel guidelines for selective cholesterol screening in children may be warranted.

Analysis of Variance↗

PubMed1999

Mechanisms underlying the inhibitory effect of propofol on the contraction of canine airway smooth muscle.

BACKGROUND: Propofol has been shown to produce relaxation of preconstricted airway smooth muscle. Although the inhibition of calcium mobilization is supposed to be the major mechanism of action, the whole picture of the mechanisms is not completely clear. METHODS: Contractile response was performed using canine tracheal rings. The effects of propofol on carbachol-induced mobilization of intracellular Ca2+ and phosphoinositide hydrolysis were measured using cultured canine tracheal smooth muscle cells by monitoring fura-2 signal and assessing the accumulation of [3H]-inositol phosphates. To detect the effect of propofol on muscarinic receptor density and affinity, [3H]N-methyl-scopolamine was used as a radioligand for receptor binding assay. RESULTS: Pretreatment with propofol shifts the concentration-response curves of carbachol-induced smooth muscle contraction to the right in a concentration-dependent manner without changing the maximal response. Propofol not only decreased the release of Ca2+ from internal stores but also inhibited the calcium influx induced by carbachol. In addition, carbachol-induced inositol phosphate accumulation was attenuated by propofol; the inhibitory pattern was similar to the contractile response. Moreover, propofol did not alter the density of muscarinic receptors. The dissociation constant value was not altered by pretreatment with 100 microM propofol but was significantly increased by 300 microM (propofol, 952+/-229 pM; control, 588+/-98 pM; P<0.05). CONCLUSIONS: Propofol attenuates the muscarinic receptor-mediated airway muscle contraction. The mechanism underlying these effects was attenuation of inositol phosphate generation and inhibition of Ca2+ mobilization through the inhibition of the receptor-coupled signal-transduction pathway.

Anesthetics, Intravenous↗

PubMed1999

Spinal nitric oxide participates in the control of the blood pressure during graded hemorrhage in the conscious rat.

We sought to evaluate the role of spinal nitric oxide (NO) in the control of blood pressure in the conscious animal and determine its possible participation in the progression of hemorrhagic shock. Adult, male Sprague-Dawley rats were chronically prepared with intrathecal, intravenous, and intra-arterial catheters. We first investigated the role of spinal NO on blood pressure control by intrathecal administration of N(G)-nitro-L-arginine methyl ester hydrochloride (L-NAME) at 0.37 micromol, 0.74 micromol. or 1.48 micromol. A dose-related increase in blood pressure was observed. We next pretreated animals with intrathecal or intravenous L-NAME at 0.37 micromol and induced the animal to shock by graded hemorrhage. Animals that received vehicle control or intravenous L-NAME had a decrease in blood pressure after 12% of the total circulatory blood volume (TBV) had been removed and developed severe hypotension after 24% TBV was bled. On the other hand, intrathecal pretreatment of L-NAME significantly attenuated the decrease in blood pressure. The blood pressure was maintained until 40% TBV had been withdrawn. We concluded that inhibition of NO synthase, in the spinal cord, increased blood pressure in a dose-dependent manner, and hemorrhagic shock induced by graded hemorrhage may involve an upregulation mechanism of spinal NO synthase in producing severe hypotension in conscious rats.

Animals↗

PubMed1999

Ileal aberrant pancreas induces intussusception and gastrointestinal bleeding in an adult woman--case report.

Aberrant pancreas is a congenital anomaly. In surgical series, its incidence varied from 0.2 to 0.8%. About 70% of aberrant pancreas occur in the gastrointestinal tract. Eighty percent of them locate in the stomach and duodenum, and only 0.2% in the ileum. We report on a 25-year-old woman with ileal aberrant pancreas who suffered from ileal intussusception and recurrent gastrointestinal bleeding. The diagnosis was confirmed by surgery and histology. She is symptom-free after surgery.

Adult↗

PubMed1999

Model-free functional MRI analysis using Kohonen clustering neural network and fuzzy C-means.

Conventional model-based or statistical analysis methods for functional MRI (fMRI) suffer from the limitation of the assumed paradigm and biased results. Temporal clustering methods, such as fuzzy clustering, can eliminate these problems but are difficult to find activation occupying a small area, sensitive to noise and initial values, and computationally demanding. To overcome these adversities, a cascade clustering method combining a Kohonen clustering network and fuzzy, means is developed. Receiver operating characteristic (ROC) analysis is used to compare this method with correlation coefficient analysis and t test on a series of testing phantoms. Results shown that this method can efficiently and stably identify the actual functional response with typical signal change to noise ratio, from a small activation area occupying only 0.2% of head size, with phase delay, and from other noise sources such as head motion. With the ability of finding activities of small sizes stably this method can not only identify the functional responses and the active regions more precisely, but also discriminate responses from different signal sources, such as large venous vessels or different types of activation patterns in human studies involving motor cortex activation. Even when the experimental paradigm is unknown in a blind test such that model-based methods are inapplicable, this method can identify the activation patterns and regions correctly.

Adult↗

PubMed1999

A retrospective study of clozapine and urinary incontinence in Chinese in-patients.

OBJECTIVE: This study investigated the incidence of clozapine-associated urinary incontinence (UI) in schizophrenic patients, the percentage of these patients with persistent urinary incontinence (PUI), and the possible factors affecting the occurrence of UI. METHOD: A total of 61 Chinese in-patients with schizophrenia (according to DSM-IV) treated with clozapine for more than 3 months were assessed retrospectively for the occurrence of UI. Patients who still had UI at the time of assessment were classified as having PUI. Patients whose UI had resolved at the time of assessment were classified as having self-limited urinary incontinence (SUI). We compared the characteristics of UI and non-UI cases and of PUI and SUI cases. RESULTS: The results showed that urinary incontinence developed at some time in 27 of 61 patients (44.3%), and that it was persistent in 15 of 61 patients (25%). There were no statistically significant differences in age, sex, clozapine dose, duration of clozapine use, duration of index admission, duration of illness, age at onset of schizophrenia, or concurrent treatment with other psychiatric medications between the UI and non-UI groups and between the PUI and SUI groups. CONCLUSION: Clozapine-associated urinary incontinence may be persistent in some patients, and it should be cautiously monitored in every patient taking clozapine.

Adult↗

PubMed1999

Adenomatoid hyperplasia in the mandibular retromolar area. Case report.

This paper reports a case of adenomatoid hyperplasia of minor salivary glands in the retromolar area, with a unique symptom of painful swelling. This appears to be the first reported case in the Chinese population. It would be useful for clinical dentists to be aware of this tumour.

Diagnosis, Differential↗

PubMed1999

Evaluation of the antioxidant activities of Erycibe obtusifolia.

Free radicals may be involved in various pathogenesis processes. Tissue damage and cellular toxicity of some chemicals mediated by oxygen free radicals can be monitored by studying the levels of lipid peroxidation in the tissues. The study reported here is to investigate the MDA concentrations in different tissues after various doses of Erycibe obtusifolia (EO) treatments. EO given at doses of 10, 20 and 30 mg/kg body weight is experimentally tested through oral administration. The antioxidant effect of EO extract is assessed by the measurements of hepatic, renal and splenic lipid peroxides (measured as malondialdehyde; MDA) after treatments. The results show no significant time-related and dose-dependent increase or decrease of MDA concentrations in the liver, kidney and spleen after EO administrations, respectively. The peak of antioxidant activities is found on the first day and the 6 hrs after treatments for liver and kidney, respectively. In contrast, the MDA concentrations in spleen after EO administrations remained above the normal values. This result suggests that a high dose of EO administration may contribute a little antioxidant activity in both liver and kidney.

Animals↗

PubMed1999

The anti-inflammatory and hepatoprotective effects of fractions from Cudrania cochinchinensis var. gerontogea.

Various fractions of the ethanol extract from the root wood of Cudrania cochinchinensis var. gerontogea (Moraceae) were evaluated for their anti-inflammatory effects on carrageenan-induced edema and hepatoprotective activities on carbon tetrachloride (CCl4)-induced and D-galactosamine-(D-GalN) induced acute hepatotoxicity in rats. The fractions (n-hexane, CHCl3, EtOAc, n-BuOH, and H2O) displayed significant inhibitory activity against carrageenan-induced edema, and the active anti-inflammatory components were further localized in the n-BuOH fraction, which exhibited the greatest anti-inflammatory effect, an effect 5% greater than indomethacin (which was used as a standard reference substance). Each fraction exerted a significant hepatoprotective effect by reducing enzymatic alteration (sGOT and sGPT) and by improving hepatic lesions, including liver centrilobular inflammation, cell necrosis, fatty change, ballooning degeneration in CCl4-induced acute hepatitis; and necrosis of the portal area in D-GalN-induced acute liver injury. The n-BuOH and EtOAc fractions had the greatest hepatoprotective effects on CCl4-induced liver injury; in contrast, the CHCl3 fraction was most potent against D-GalN intoxication, which is comparable to silymarin, as a recognized hepatoprotective drug.

Alanine Transaminase↗

PubMed1999

Effects of punicalagin and punicalin on carrageenan-induced inflammation in rats.

Punicalagin and punicalin were isolated from the leaves of Terminalia catappa L. In this study, we evaluated the anti-inflammatory activity of punicalagin and punicalin carrageenan-induced hind paw edema in rats. After evaluation of the anti-inflammatory effects, the edema rates were increased by carrageenan administration and reduced by drug treatment. After 4 hr of carrageenan administration, the best effect group was the punicalagin (10 mg/kg) treated group (inhibition rate was 58.15%), and the second was the punicalagin (5 mg/kg)-treated group (inhibition rate was 39.15%). However, even if the anti-inflammatory activity of punicalagin was the same as punicalin at the 5 mg/kg dose, the inhibition effect from larger doses of punicalagin was increased, but there was a decrease with a larger dose of punicalin. The data showed that both punicalagin and punicalin exert anti-inflammatory activity, but treatment with larger doses of punicalin may induce some cell damages.

Animals↗